2 Answers
2

I always copy system files from a known clean PC with the same OS and service pack level, system files on the DVD are usually outdated. SFC may work, unless the virus infected those stored backups of windows system files.

When in doubt, back up personal data and wipe the drive and re-install the OS clean, scan backed up files before transferring them to the clean installed system.

Thanks for the tip. I forgot that files on the DVD can be much older than what's available through Update and restoring them from a DVD could introduce some inconsistency with the rest of the system. So running "sfc /scannow" and saving the output to a remote host is a better option.
– OverTheRainbowJan 29 '12 at 16:28

scannow will replace any system files that are corrupt or the wrong version, but like I said before, what if the copies it uses to replace them are infected also...personally I wipe and re-install the OS when infected.
– MoabJan 29 '12 at 18:04

Mmm... So there's no reliable way other than reformating the drive and reinstalling from scratch. Thanks for the input.
– OverTheRainbowJan 29 '12 at 22:00

I would not say that, its just my way of dealing with an infection on my personal computers. Some infections are very hard to remove completely and you cannot be 100% sure its gone unless you clean install.
– MoabJan 29 '12 at 23:39